用高效SiO_2载体催化剂进行乙烯气相聚合

ETHYLENE GAS PHASE POLYMERIZATION OVER HIGHLY ACTIVE SiO 2 SUPPORTED CATALYST

使用球形ＳｉＯ２负载ＭｇＣｌ２－ＴｉＣｌ４高活性催化剂进行乙烯气相聚合，考察了催化剂制备条件和添加剂对催化剂的组成、催化活性以及聚合表观动力学的影响．结果表明，ＳｉＯ２热处理温度和所用的醇对Ｍｇ和Ｔｉ的负载量及乙烯聚合活性有明显的影响．催化剂制备中添加Ｌｅｗｉｓ酸ＳｉＣｌ４或ＡｌＥｔ２Ｃｌ能大幅度提高催化剂的活性，其中以ＳｉＣｌ４的效果最为明显．随着ＳｉＣｌ４用量的增加，乙烯气相聚合的活性显著提高。

Ethylene gas phase polymerization was carried out over highly active SiO 2 supported catalyst obtained by supporting MgCl 2 alcoholates on spherical SiO 2 and treating with TiCl 4 and activators. The effects of preparation condition and activator amount on the catalyst composition, the activity for C 2H 4 gas phase polymerization and the polymerization kinetic curves were studied. Raising the calcination temperature for SiO 2 resulted in lower Ti and Mg content in the catalyst and higher catalytic activity. The addition of Lewis acids, such as SiCl 4 and AlEt 2Cl, in the catalyst preparation has a significant effect on the catalyst composition and the catalytic activity. It was found that SiCl 4 was an effective activator. With increasing the added SiCl 4 amount, the activity for C 2H 4 gas phase polymerization increased and the kinetic behavior of the polymerization changed from the steady type to decay type.